WASHINGTON (AFP) - The asteroid 433 Eros is a solid mass of iron-bearing minerals, according to the first data transmitted back to earth from the Near Earth Asteroid Rendezvous (NEAR) space probe orbiting it.
"Work is just starting, but it's already clear that Eros is much more exciting and geologically diverse than we had expected," said NEAR mission's lead scientist, Andrew Cheng of the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland.
Though small among celestial bodies, the asteroid is shaped like a giant potato, 33 kilometers (20.5 miles) long and 13 kilometers (8 miles) wide, twice the size of the peninsula of Manhattan in New York. The asteroid has been found to have a mass of 2.4 grams per cubic centimeter, approximately the same bulk density as the earth's crust.
"With this new data, it now looks like we have a fairly solid object," said the leader of the project's radio science team, Donald Yeomans of NASA's Jet Propulsion Laboratory in Pasadena, California.
Its formation therefore appears to be very different from that of the asteroid Mathilde, which the NEAR probe surveyed in 1997 and found to be made up of various pieces of rock. "There is no strong evidence that it's a rubble pile like Mathilde," said Yeomans.
The large number and concentration of craters suggest that 433 Eros is a relatively old asteroid, he said. Uniform grooves across its craters and ridges hint at a global fabric and, perhaps, underground layers. The NEAR probe has detected the presence of various types of rock, including the iron-bearing mineral pyroxene and olivine. NEAR is scheduled to orbit 433 Eros for a year
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